White adipose tissue (WAT) remodeling is an emerging therapeutic strategy for treatment of obesity-related disorders like diabetes. Remodeling of WAT by beta3 adrenergic activation is a robust model that allows mechanisms to be tested in vivo and in vitro. Using this model system, the progenitors of the brown adipocytes that appear in WAT were identified, and techniques for imaging, isolating, and genetically manipulating these cells in vivo were developed. These cells appear to act as adult 'remodeling stem cells' (rmSC) that are likely involved in the remodeling and cellular restoration of WAT under various conditions. This project will examine mechanisms by which these novel rmSC are recruited by WAT therapeutic remodeling and by chronic high fat feeding. The long term goal is to guide strategies for expanding metabolically desirable adipocyte phenotypes for treating obesity-related disorders.